Catalytic membrane reactors are useful for producing hydrogen gas, a green energy source.
A conventional membrane reactor typically contains a catalyst bed, either packed inside the tubular support of the reactor or arranged outside the tubular support, and a palladium or palladium-alloy membrane coated on the outer surface of the tubular support. The membrane reactor converts hydrocarbons to hydrogen gas by the reforming reaction in the catalyst bed. The hydrogen gas thus generated is separated from the reaction mixture through the palladium or palladium-alloy membrane. See Amiridis et al., International Patent Application Publication WO 1999/043610 A1; and Hattori et al., US Patent Application Publication US 2008/0241058 A1.
During the reforming reaction, residual carbonaceous materials, formed and deposited in the catalyst bed, cause coke formation, which gradually deteriorates catalyst efficiency and leads to a dangerous pressure build-up inside the membrane reactor. Further, in a conventional membrane reactor, the palladium or palladium-alloy membrane is subjected to cracking as it is on the outside surface of the tubular support and exposes to catalyst particles and high temperature. Such reactors are therefore not durable. See Nakamura et al., US Patent Application Publication 2008/0226544 A1.
There is a need to develop a safe and durable membrane reactor useful for producing hydrogen gas.